Running in races unfit is what its all about. Its far, far, far tougher than actually running in them when you're fit... which is just a doddle
.
Full body cramps, knife stabbingly horrendous cramp in your calves, dehydration, legs collapsing underneath you, not being able to move at all at the end but just lying there groaning, taking 20 minutes to bend your body sufficiently to get in your car to go home, hypothermia, double vision, full frontal body grazes, chaffage above and beyond human endurance, bleeding nipples, falls on rocks, falls in bogs, falls in rivers, crashes descending, mud up to your neck, twisted ankles, frozen hands, hit by falling rubble, near misses from dislodged boulders............ (and so on and so on).
And I think I did them all in one race once